Low-ceiling prospects ready to help

Last week's midseason ranking of the top 50 prospects in the minors left off a number of lower-upside players in the high minors who are very close to contributing in the big leagues. Here are five such players who could see real major league time this year, plus one more of note who's league-ready but is probably trade bait instead.

Paul Goldschmidt, 1B, Arizona

Goldschmidt has plus raw power and a pretty good idea of the strike zone, which should combine to give him a pretty healthy MLB career as at least a solid backup. Whether he's more than that depends on whether his fringy bat speed will play enough to let him get to that power -- and with a fair number of soft-tossers kicking around the National League, he might be able to make it work. He's a below-average defender at first who might have to DH, and could end up as more of a right-handed platoon/bench bat who starts against lefties. Arizona has gotten just a .241/.312/.398 line from its first basemen this year, and I do think Goldschmidt could exceed that low bar if given the chance.

Kyle Gibson, RHP, Minnesota

Like Goldschmidt, Gibson's real problem is a lack of upside, as he hasn't really added to his fastball since his sophomore year of college and is now a command/control right-hander who should eat up innings but probably won't be more than a solid 3 in a big league rotation. He works down in the zone, getting some groundballs, and has a solid-average changeup and a curveball with good shape, although that also hasn't evolved into the plus pitch I thought it would. But the combination of low walks and an above-average groundball rate should make him at least a useful back-end starter right now, and he's a much better option for the Twins' rotation than Scott Diamond.

Brad Boxberger, RHP, Cincinnati

Boxberger was miscast as a starter in the low minors but has flourished this year in his second stint as a reliever with Double-A Carolina. He'll sit at 92-94 mph and flash a little better with a plus breaking ball, shaped like a curveball but at slider velocity, emasculating right-handed hitters, who hit .094/.171/.125 against him in Double-A and are 2-for-14 with six punchouts so far in Triple-A. His changeup remains a below-average offering and left-handed hitters have done more damage, although not nearly enough to consign him to specialist duty yet. The Reds don't have a lot of swing-and-miss in their bullpen at the moment -- only Aroldis Chapman has struck out at least a quarter of the men he's faced, and unfortunately he's walked more than a quarter of them as well -- and Boxberger could help them in a middle relief role this year.

Wilin Rosario, C, Colorado

The Rockies have never been able to live with what Chris Iannetta can't do (hit for average, control the running game) and focus on what he can (get on base, hit for some power), and they certainly seem to favor Rosario as their catcher of the future. Rosario does two things Iannetta doesn't: He has nailed 40 percent of opposing base-stealers as a pro, and his .256 average in Tulsa this year is his worst since 2007. And Rosario has at least average power right now, with 15 HRs in a half-season as a Double-A repeater. However, Rosario is rocking just a .300 OBP right now, and still has yet to play more than 73 games in a regular season due to injuries, so his long-term projection is pretty cloudy. For this year, I'd expect him to struggle to get on base enough to help the team, but given Jim Tracy's clear dislike for Iannetta's game, I wouldn't be surprised at all to see Rosario in the majors.

Yonder Alonso, 1B, Cincinnati

The other players on this list are more likely to debut for their parent clubs than for others, but Alonso looks more like trade bait, as he's completely blocked by last year's NL MVP, Joey Votto, and is unlikely to be able to play left field well enough to profile there in the majors. (That's even more true now as teams are shifting back to playing good defenders in left, as opposed to sticking a bat out there and hoping he catches anything hit right at him.) Alonso is hitting well and getting on base while repeating Triple-A, and in a small sample it seems that his troubles with left-handed pitching might be behind him, as he's hit .311/.383/.544 in 103 at-bats against southpaws this year with just 19 strikeouts. He could start at first base for a handful of clubs right now and would do so for the minimum salary through 2014, which makes him a very valuable trade asset, and one I'd expect the Reds to cash in to try to return to the postseason this year.